The invention relates to foil printing and in particular to transferring foil color from a foil and adhering the color to portions of an image.
In foil printing, a colored foil bonded to a backing, hereinafter referred to as a xe2x80x9cfoil backingxe2x80x9d is transferred from the foil backing to a substrate to form an image or parts of an image on the substrate. Hereinafter, the colored foil and its foil backing are referred to as a xe2x80x9cprinting foilxe2x80x9d. In foil printing on paper, generally, the paper is printed with a desired image using a conventional printing press and conventional printing inks. The image is then printed with an adhesive, hereinafter referred to as a xe2x80x9cfoiling adhesivexe2x80x9d, in those areas of the image to which it is desired to transfer the foil. The foiling adhesive is usually a dry toner xe2x80x9cprintedxe2x80x9d in a xerographic process, in which the toner is bonded to the paper by fusing. A printing foil having a desired color foil is then pressed to the paper and heated. The heating causes the printed toner to melt and become tacky. The printing inks on the other hand are substantially unaffected by the heat and pressure. The foil sticks to the tacky toner but not the printed inks. When the printing foil is removed, foil detaches from the foil backing and adheres to the foiling adhesive to cover the areas of the image that it is desired to foil print. Foils are generally metallic and are often used for special printing effects, such as for example, to print gold and purple metallic color details on feathers of an image of a peacock or to gild a name on a business card.
When foil printing an image, the transfer of a foil to only desired areas of the image requires that areas of the image that are not to be foil printed not stick to the foil when the printing foil bearing the foil is pressed to the image and heated. In many printing processes an image is printed on paper by depositing toners of appropriate colors on the paper and fusing the toners to the paper. Toners used to print an image are fused to paper similarly to the way that toner used as a foiling adhesive in a conventional foil printing process is bonded to a printed image. If a printing foil is pressed to an image printed with toners and heated, the toner melts and foil adheres to all printed areas of the image that contact the printing foil. When an image is printed with toners it is therefore not practical to foil print only parts of the image using conventional foil printing processes. It is certainly not practical to foil print only fine details of such an image, such as for example details of the feathers of the peacock image noted above.
An aspect of some preferred embodiments of the present invention relates to providing a method for foil printing selected areas of an image printed with toners.
An aspect of some preferred embodiments of the present invention relates to providing a foiling adhesive for foil printing the image that has a melting temperature that is less than the melting temperature of the toners used to print the image.
To foil print an image printed with the toners the foiling adhesive is printed on those areas of the image to which it is desired to apply a foil. A printing foil is pressed to the image and heated to a temperature that is above the melting temperature of the foiling adhesive and below the melting temperature of the toners. The foiling adhesive becomes tacky and sticks to the foil. The toners do not become tacky and do not stick to the foil because the temperature to which the printing foil is heated is below the melting temperature of the toners. When the printing foil is removed from the image, after cooling, foil is left only on those areas of the image printed with the foiling adhesive.
An aspect of some preferred embodiments of the present invention relates to providing a printing foil having its foil covered with a protective xe2x80x9cnon stickxe2x80x9d layer that retards adhesion of the foil to the toners but not to the foiling adhesive when the printing foil is pressed to the image and heated.
In a preferred embodiment of the present invention, the foiling adhesive has a higher melting temperature than the toners used to print the image. When the printing foil is pressed to the image and heated to a temperature above the melting temperature of the adhesive its foil sticks to the adhesive but not to the toners. During heating of the printing foil, heat from the foil softens the toners. Preferably, the toners are highly viscous at the melting temperature of the adhesive so that the toners do not flow during the foil printing process.
There is therefore provided in accordance with a preferred embodiment of the present invention a method for producing a printed image having a region that is foil printed comprising: printing at least one region of the image with a toner; printing the region of the image to be foil printed with a foiling adhesive that sticks to a foil on a printing foil, which adhesive has a melting temperature lower than the melting temperature of the toner; and pressing the printing foil to the image and heating the printing foil to a temperature greater than the melting temperature of the foiling adhesive and less than the melting temperature of the toner.
Preferably, the toner comprises a material from the group of materials consisting of ethylene methacrylic acid copolymer and ionomers of ethylene methacrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises ethylene methacrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises an ionomer of ethylene methacrylic acid copolymer.
Alternatively or additionally the adhesive comprises a material chosen from the group of materials consisting of: ethylene acrylic ester maleic anhydride terpolymer; low molecular weight ethylene acrylic acid copolymer; ionomers of low molecular weight ethylene acrylic acid copolymer; and esters of ethylene acrylic acid copolymer.
In some preferred embodiments of the present invention the adhesive comprises ethylene acrylic ester maleic anhydride terpolymer. In some preferred embodiments of the present invention the adhesive comprises low molecular weight ethylene acrylic acid copolymer. In some preferred embodiments of the present invention the adhesive comprises an ionomer of low molecular weight ethylene acrylic acid copolymer. In some preferred embodiments of the present invention the adhesive comprises an ester of ethylene acrylic acid copolymer.
There is further provided in accordance with a preferred embodiment of the present invention a method for producing a printed image having a region that is foil printed comprising: printing at least one region of the image with a toner; printing the region of the image to be foil printed with a foiling adhesive; covering a foil side of a printing foil with a layer of material that sticks to melted foiling adhesive but not to the toner; and pressing the printing foil to the image and heating the printing foil to a temperature greater than a tacking temperature of the foiling adhesive.
Preferably the layer of material that doesn""t stick to toner comprises a material chosen from the group of materials consisting of: methacrylic copolymer resin; polyester; polyvinyl chloride; and polycarbonate.
In some preferred embodiments of the present invention the non-stick layer comprises methacrylic copolymer resin. In some preferred embodiments of the present invention the non-stick layer comprises polyester. In some preferred embodiments of the present invention the non-stick layer comprises polyvinyl chloride. In some preferred embodiments of the present invention the non-stick layer comprises polycarbonate.
Additionally or alternatively the toner comprises a material chosen from the group of materials consisting of: ethylene methacrylic acid copolymer and ionomers of ethylene methacrylic acid copolymer; low molecular weight ethylene acrylic acid copolymer and ionomers of low molecular weight ethylene acrylic acid copolymer, esters of ethylene methacrylic acid; and esters of ethylene acrylic acid.
In some preferred embodiments of the present invention the toner comprises ethylene methacrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises ionomer of ethylene methacrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises low molecular weight ethylene acrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises an ionomer of a low molecular weight ethylene acrylic acid copolymer. In some preferred embodiments of the present invention the toner comprises an ester of ethylene methacrylic acid. In some preferred embodiments of the present invention the toner comprises an ester of ethylene acrylic acid.
Additionally or alternatively, the adhesive comprises a material chosen from the group of materials consisting of styrene acrylic acid copolymer; polyamide; ethylene acrylic ester maleic anhydride terpolymer. In some preferred embodiments of the present invention the adhesive comprises styrene acrylic acid copolymer. In some preferred embodiments of the present invention the adhesive comprises polyamide. In some preferred embodiments of the present invention the adhesive comprises ethylene acrylic ester maleic anhydride terpolymer.
There is further provided in accordance with a preferred embodiment of the present invention a printing foil for foil printing a region of an image comprising: a substrate; a layer of foil bonded to the substrate; and a layer covering the foil formed from a material chosen from the group of materials consisting of methacrylic copolymer resin, polyester, polycarbonate and polyvinyl chloride.
In some preferred embodiments of the present invention the layer covering the foil comprises methacrylic copolymer resin. In some preferred embodiments of the present invention the layer covering the foil comprises a polyester. In some preferred embodiments of the present invention the layer covering the foil comprises polycarbonate. In some preferred embodiments of the present invention the layer covering the foil comprises polyvinyl chloride.